Department of Environmental and Occupational Health, Indiana University-Bloomington School of Public Health, Bloomington, IN, USA; Global Environmental Health Research Laboratory, Indiana University-Bloomington School of Public Health, Bloomington, IN, USA.
Department of Environmental and Occupational Health, Indiana University-Bloomington School of Public Health, Bloomington, IN, USA; Global Environmental Health Research Laboratory, Indiana University-Bloomington School of Public Health, Bloomington, IN, USA.
Int J Hyg Environ Health. 2021 Jun;235:113770. doi: 10.1016/j.ijheh.2021.113770. Epub 2021 May 24.
Lead and other toxic and potentially toxic metals and metalloids are significant contributors to the global burden of disease and disability. Studies characterizing blood metal/metalloid levels and potential sources of environmental exposures are limited for populations living in the major urban centers of Andean-area countries.
We used ICP-MS to quantify blood levels of lead (PbB), cadmium (CdB), manganese (MnB), total arsenic (AsB), and total mercury (HgB) in school-age children (n = 47) and their reproductive-age mothers (n = 49) from low-resource households in Quito, Ecuador. These were compared to published 95th percentile reference values (RV) and for PbB, also to CDC reference values. We used a detailed environmental questionnaire to examine the contribution of residential and neighborhood environmental exposure sources with participant blood metal/metalloid levels. We used ICP-MS to measure Pb levels in residential windowsill dust, floor dust, and drinking water samples and used XRF for paint samples.
Forty-five percent of the mothers had PbBs ≥ 5 μg/dL; 14.3% had PbBs ≥10 μg/dL. Maternal blood levels exceeded RV for PbB (76%), CdB (41%), MnB (88%), HgB (57%), and AsB (90%). Of children, 68% had PbBs ≥ 5 μg/dL, and 21.3% had PbB ≥10 μg/dL. Most child blood levels exceeded the RV for PbB (100%), CdB (100%), MnB (94%), and total HgB (94%) and AsB (98%). Most mothers (97%) and all children had blood levels indicating exposure to multiple metal/metalloid mixtures. Maternal and child PbBs were moderately correlated with each other but the other four metals/metalloids were not. Factors associated with maternal blood metal/metalloid levels were residence in a home with an earthen floor (PbB) or bare cement block walls (MnB), living near a dirt-paved or cobblestone street (PbB), <50 m from a heavily trafficked major roadway (PbB, HgB), living in the Los Chillos (PbB) or Cotocollao neighborhoods (PbB, HgB), or in areas where street vendors grilled food using charcoal (MnB). Factors associated with child blood metal/metalloid levels were residence in a dirt floor home (PbB, CdB, AsB), living near a dirt-paved or cobblestone street (PbB), living in the El Camal or Cotocollao neighborhoods (AsB), or in local neighborhoods where scrap metal smelters (MnB) and LPG gas depositories (PbB) were present.
The elevated blood levels of PbB, other metal/metalloids, and metal/metalloid mixtures identified mothers and children in this exploratory study is an urgent public health and clinical concern. The exposure patterns suggest that traffic-related exposures, especially the resuspension of legacy Pb in dust, as well as other anthropogenic and geogenic sources may be important environmental contributors to metal/metalloid exposures in urban Ecuadorian mothers and children. Future studies are needed to confirm these findings and explore other potential exposure sources. Biomonitoring is also needed in order to formulate effective intervention strategies to reduce population exposure to toxic levels of environmental metals/metalloids.
铅和其他有毒及潜在有毒金属和类金属是全球疾病和残疾负担的重要因素。针对居住在安第斯地区国家主要城市中心的人群进行血液金属/类金属水平特征描述及其环境暴露来源的研究十分有限。
我们使用电感耦合等离子体质谱法（ICP-MS）对厄瓜多尔基多来自低收入家庭的学龄儿童（n=47）及其育龄母亲（n=49）的血液中铅（PbB）、镉（CdB）、锰（MnB）、总砷（AsB）和总汞（HgB）水平进行了定量分析。将这些结果与已发表的第 95 百分位数参考值（RV）进行了比较，对于 PbB 还与疾病预防控制中心（CDC）的参考值进行了比较。我们使用详细的环境调查问卷，研究了住宅和邻里环境暴露源对参与者血液金属/类金属水平的影响。我们使用 ICP-MS 测量了住宅窗台灰尘、地板灰尘和饮用水样本中的 Pb 水平，并使用 X 射线荧光光谱法（XRF）测量了油漆样本中的 Pb 含量。
45%的母亲血液中的 PbB 水平≥5μg/dL；14.3%的母亲血液中的 PbB 水平≥10μg/dL。母亲血液水平超过了 PbB（76%）、CdB（41%）、MnB（88%）、HgB（57%）和 AsB（90%）的 RV。在儿童中，68%的儿童血液中的 PbB 水平≥5μg/dL，21.3%的儿童血液中的 PbB 水平≥10μg/dL。大多数儿童的血液水平超过了 PbB（100%）、CdB（100%）、MnB（94%）和总 HgB（94%）和 AsB（98%）的 RV。大多数母亲（97%）和所有儿童的血液中都显示出暴露于多种金属/类金属混合物的迹象。母亲和儿童的 PbB 水平之间存在中度相关性，但其他四种金属/类金属则没有。与母亲血液金属/类金属水平相关的因素包括居住在有土制地板的房屋（PbB）或裸露水泥墙的房屋（MnB）、居住在铺有泥土或鹅卵石街道附近（PbB）、距离繁忙的主要道路<50m（PbB、HgB）、居住在洛斯奇洛斯（PbB）或科托科拉略（PbB、HgB）社区或居住在摊贩使用木炭烧烤食物的地区（MnB）。与儿童血液金属/类金属水平相关的因素包括居住在泥土地板房屋（PbB、CdB、AsB）、居住在铺有泥土或鹅卵石街道附近（PbB）、居住在埃尔卡马勒或科托科拉略社区（AsB）或居住在当地社区存在废金属冶炼厂（MnB）和液化石油气储存库（PbB）。
本探索性研究中确定的母亲和儿童血液中 PbB、其他金属/类金属及其混合物的升高水平是一个紧急的公共卫生和临床问题。暴露模式表明，交通相关暴露，特别是灰尘中遗留 Pb 的再悬浮，以及其他人为和地质来源，可能是厄瓜多尔城市母亲和儿童金属/类金属暴露的重要环境因素。需要进一步研究来证实这些发现，并探索其他潜在的暴露源。生物监测也需要制定有效的干预策略，以减少人群对环境金属/类金属的毒性暴露。
